Sliding hoisting clamp



Jan. 22, IV THOMPSON v SLIDING HOI'STING CLAMP v Filed Nov. 17, 1944 2 Sheets-Sheet l Jan. 22, 1946. v. THOMPSON 2,393,430 SLIDING HOISTING CLAMP Y Filed Nov. 17, 1944 v 2 Sheets-Sheet 2 Inventor I By I v I M Attorney instantly releasable and object being lifted when no lifting efiort is present.

Patented Jan. 22, 1946 I u I Manitoba, Canada; 1 Application November 17, 194 4, Serial:

The main objectof the invention resides in the provision of highly efflcient'clam'ping means for lifting pipes and the like. I 1

Another object is the provision of such a clamp which is quickly operable, rugged and of simple 'characten- I v .2

-' A further object relates to-a clamp of the charact'er described havingclamping -means' devoid of teeth or other object-marking devices.

Still another object concerns a hoisting clamp still-further object contemplates a hoisting clamp which can be made at relatively low cost. Other objects and advantages of the invention will become apparent, or be pointed out further,

during the description to follow.

As an example, and for purposes of illustration only, a preferred embodiment of the invention is shown in the annexed drawings, wherein:

Figure 1 is a side elevational view of the clamp according to the invention,

Figure 2 is an elevational view of said clamp, seen from the rear and with a portion of the housing bail cut away,

Figure 3 is an elevational view similar to Figure 1, with a portion of the housing bail cut away to show the clamp in operative position, and

Figure 4 is a similar view but showing the clamp mechanism in inoperative locked position.

Referring to the drawings,- wherein similar reference characters represent corresponding parts throughout, the letter A generally indicates an object like, said object being, in the present instance, a tube for well-drilling purposes. As shown in Figure l, the tube A is engaged by the clamp,

said clamp being hoisted or lifted by means of the hook H engaging the screw-eye 5 bolted or otherwise secured to the uppermost portion of the casing bail indicated generally by the reference letter B. o

The housing proper consists of two side parallel cheeks 6, slightly concave, and joined together at the top by means of a narrow cross bridge I to which the screw eye 5' is secured, and by means of a rear web 8 and a front narrow web 9 defining therebetween and the bridge "I an opening 10 through which the object to be lifted is intendedto project. The lower portions of the checks are thickened at H to form easily slidable on the being lifted such as a rod or the a support for the arm bolt 12 threadedly engaged with one of said enlargements l l.

-' --The-bolt l2 serves as the pivot for pair of parallel-links l5 .freelymounted on said bolt and in operation, grips there is formed a hold in-spaced alignment from each other by 'the flxed washer It." said links support, at the free end thereof, therebetween, the inner end of an arm H, which extendsupwardly from said linksandis pivoted thereto by means of a rivet 'orthe like l8. ,Asshown' toadvantage in Figur'es 3 andil theupp'er end of the arm I1 is bent -angularly so thattheibent'portionlies in .a' plane parallel with the axis of the'object being lifted,

when in operative position. 'Said bent portion, 'lorJfinger, indicated at 20 inthe drawings, is apertured: to -head' 22 projecting on .the held :-in .place by a nut .23. "This .stud isprefergablyfof highlyitemperedtsteel to resist wear and receive 'a'. threaded stud 2llhaving a side of theobject and also to prevent marking the rod or pipe being handled, as well as to enable adjustment of the clamping action without recourse ,to machining operation on the finger '20.

Integrally formed with the arm 11, just below the juncture of said am with the finger 20, forwardly projecting ring 25 disposed in a planeparallel with that of the bolt 2| and suitably reinforced on the arm proper to insure the proper solidity. This ring, therefore, is movable as a unit with the arm I! and provides one of the three contact points which,

the object to be lifted.

The device is completed by a U-shaped sleeve 21 and cars 28 projectboth sides thereof, and bolt l2 which, thus, in position. As shown in Figures 1, 3 and 4, the sleeve is provided, at

the upper end thereof, with a short integral tube 29, adapted to guide a spring 30 which is I attached at one end to the upper part of the web 21 and hooked at the other end to the front portion of the ring 25, as shown in Figures 3 and 4.

Disposed between the links I5, approximately midway between the bolt l2 and the rivet l8, there is pivoted at 35 a hook 36 adapted to engage a notch 31 formed in the lower end of the arm ll. The purpose of this hook is to hold the clamp in inoperative position (shown in Figure 4) the arm in this position being prevented from rotating around the rivet l8 and, furthermore, abutting against the stop pin 38 also disposed between the links l5. Inasmuch as in this extended position of the arm I! the spring 30 is extended also, this spring has a tendency to swing the arm I! out of the housing, especially when the object or pipe A is removed from the clamp. In order to prevent this swinging motion, a second stop pin 40 is provided between the cheeks of the housing and adapted to contact the links l5 and hold the same in the position indicated in Figure 4. The arm being held e evatedinlinoperati ep i on, anrt biet inipe or the like, can he slid within the-ring fiiand the clamp lowered or raised thereon 'for proper positioning without any clamping action being present.

The operation of the clamp should-1be. .obyiol1s from an examination of Figures 3 and 4; when the rod A is inserted within thering 25; and the catch 36 released, the spring 30 will urge the ring downwardly and cause theehead jflvto 120111 tact the rod which, furthermore, is caused toabut,

against the bolt I2. Consequently, three points f. Contact en a erth rod points ammonstit ted by the medal-2;thetputerainner:maxzin f the ring 25 and saidb lt 'Z. Assumingt a lifting: strain is exerted on; the hQQ fHi housin will, tend to .be-llifted and; carry-fillers.-

with the bolt-.12; 'lhismovement :willjbayeifo an effect til further articulate the. arm. ;I l causin a pressing; action ,of point: 22: against the.- rod, which actionis, of course; .resistedl'bythearing 25. As a result, the roads-gripped between-said three points-and the. greater the lifting; action, thegreater will: "be the clamping effect. between the. three. points. mentioned.

From theioregoing, it 1, will beevident that the present. invention is van advance. in the art '-.o1'

liiting. clamps, inthat :said clamp constituted of. .a minimum of parts and adapted togrip -elon gated;and smooth objects solely-by means tetra V clamping l action without recourse to gripping teeth or the like devices liable to mar or otherwise distort objects being lifted.

It is to be understood that the form of my invention herein shown and described is to be taken as a preferred example of the same, and that various changes as to the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the s oveeoithe su lioin claims...

' Hevi sithus-fleswihedmy invention, 1 claim:

1; A' hoisting clamp, comprising a housing, a

link pivoted to the bottom of the housing, an

arm pivoted to said link, a ring extending from thesffreetend of the arm at right angles thereto, meansfor causing downward movement of the ring and arm; and means at the top of the housmean afar; recei in eamoistina :st-rainiat hcet p not, the housing. meansifor retaining c-theaarm n vexhumed. inoperative positionr andmeansat. :the bottom or :theuhousin for pulling theehousin downwardly.

. VAUGHAN @THQMPSON. 

